In the apparel and related industries it is customary to use a so-called marker for cutting of materials or fabrics. The marker comprises a sheet of paper on which are printed in essence lines defining the contours of various pieces of fabric forming various parts of a garment which is made by sewing together such pieces of fabric. The marker is laid over a stack formed by a number of fabric layers, or in certain cases over a single fabric layer, and the fabric is cut through the marker by a cutter which follows precisely the contour lines printed thereon. For each fabric stack cutting a new marker is required because the marker is destroyed in the process and therefore it is economically necessary to use cheap paper for the marker, particularly since in many instances up to 100 or even more markers are needed to cut the number of stacks or quantity of fabric for the required number of garments.
There are various methods of imprinting the contour lines on the markers and one such method is as follows. By appropriate electronic data manipulation the contour line configuration for a specific garment is stored as a programme in a computer which operates a plotter as is well known in the art. The output from the plotter is a sheet of paper containing thereon a printout of the contour lines and such plotter output is then used as a duplicating master for generating a number of copies which then serve as markers.
Marker generation by copying from the duplicating master is carried out as follows. The plotter printout is produced by signal addressed styli contacting a dielectric paper and forming an electrostatic charge pattern thereon corresponding to the information to be printed that is the contour lines. The dielectric paper surface is then contacted with a liquid toner as is well known in the art, that is electroscopic marking particles dispersed in a so-called carrier liquid, whereby such electroscopic marking particles or toner material becomes attracted by said electrostatic charges and forms patternwise deposits on the dielectric paper surface. The toner material is of a composition adapted to form hectographic printing deposits that is to say it contains alcohol soluble dyes and thus the plotter output becomes a hectographic duplicating master for the generation of copies therefrom or markers by hectographic or so-called spirit duplication, as is well known in the art. In the process of duplication, the hectographic master is usually mounted on or passed over a rotating cylinder; the copy paper is moistened with alcohol or a mixture of water and alcohol and is brought into intimate contact with the printing surface of the master whereby the alcohol in the copy paper dissolves some of the spirit soluble dye contained in the printing deposits on said printing surface and such dissolved dye becomes absorbed by the moistened copy paper forming a dye image thereon. Upon evaporation of the alcohol the dye image becomes fixed to the copy paper. Subsequent copies are made by repeating the steps of moistening the copy paper and contacting it with the printing surface of the master.
It has been found in practice that by the above described method in many instances it is not possible to produce the required number such as up to 100 markers from one dielectric paper base hectographic master because such masters due to the nature of the dielectric paper base and hectographic toner deposit formed thereon show severe copy density deterioration after only about 15 or so copies. Thus in those instances where more than about 15 markers are required it is necessary to produce in the plotter further duplicating masters on dielectric paper, which is time consuming and expensive in view of the high cost of the dielectric paper. Thus there is need for increasing substantially the number of copies or markers which can be generated from one and the same dielectric paper base output produced in the plotter.
It is known to develop a latent electrostatic image on a dielectric sheet by a coloured toner and to electrically transfer the toner to a first and even to a second surface but this only involves transferring a single developed image at a time. Such a method is shown in the specification of Australian Letters Patent No. 469,940 and the corresponding U.S. Pat. No. 3,862,848.